[cpac]

Here's the problem:

we've got a Comcast cable modem coming in to our Airport, and we've got two Macs (a TiBook and an iBook) connecting to the internet through the airport. There is no wired LAN.

Several times per day however a bizarre thing happens: one or both of the computers, while still being connected to the Airport network, do not see the internet connection - instead giving themselves a self-assigned IP address. Another symptom is that though there's full Airport reception on the client, no base station is revealed when the Airport Admin Utility is run.

Turning Airport on the client computer off and on again does not fix the problem.

The only fail=safe fix seems to be turning off airport on both client computers, power-cycling the base station, and then turning on only one of the client computers' airport. Then, that client computer will work as expected, (the second sometimes works, and sometimes doesn't without any indication of why.

If anybody knows a fix, or has some suggestions on how to further diagnose I'd appreciate it. (The only knowledge base article I found suggested only turning the client computer's airport off and on should fix the the problem, but as I said above, it doesn't).

Thanks

PS:

both Macs are running 10.3.1
ice-colored (dual ethernet) airport
firmware v: 4.0.8

[si_lance]

Stupid question, are you using the newest Aiport software on the client machines?

[cpac]

Originally posted by si_lance:
Stupid question, are you using the newest Aiport software on the client machines?

yep.

[ghporter]

Are your computers getting their DHCP addresses from your modem or from your AirPort base?

The way to go with a cable connection is to set the ABS to "distribute IP addresses," and "share a single IP" (they're on the Network tab of the Admin Utility). This way, the client computers aren't seen by the modem (some cable providers only want one computer connected to the modem), and the ABS isolates the clients from the outside world-for security.

It also ensures that your computers get their addresses from the ABS, which is probably your problem.

[cpac]

yes, I have the ABS set to distribute IP addresses, and have it set to share a single IP.

I'm curious however, whether Comcast could still be detecting use by more than one computer, or have a very short expiration time on our IP, and thereby be causing our problems.

[jonn804]

I have the same problem (which is why I'm searching this forum). Comcast is connected to my Airport Extreme, my PowerBook works great, my G5 drops the connection several times per day. Comcast blames my AirPort ("unsupported, we can not help you"). I was ready to take my AirPort card back to Apple until I read this.

[si_lance]

Originally posted by cpac:
yes, I have the ABS set to distribute IP addresses, and have it set to share a single IP.

I'm curious however, whether Comcast could still be detecting use by more than one computer, or have a very short expiration time on our IP, and thereby be causing our problems.

I have a Netgear Wireless Router on a Comcast cable modem, and I have no such problems using a iBook w/airport and a Dell X300 w/Centrino. I am often on a VPN to work all day on the Dell and chatting/surfing on the iBook simultaneously without a hitch. Haven't rebooted the iBook for weeks (had a security update otherwise she just sleeps), but the router is solid (had to upgrade the firmware for the Centrino dropping off for some reason).

[ghporter]

Comcast shouldn't see anything but the AirPort base; it runs Network Address Translation to hide everything on the LAN side from the outside world.

[cpac]

Originally posted by GHPorter:
Comcast shouldn't see anything but the AirPort base; it runs Network Address Translation to hide everything on the LAN side from the outside world.

Ok, so the problem should probably be something on the Airport-client end of things.

Anybody have any ideas about why a client would report having full airport reception, but not be able to see the base station in the Airport Admin Utility?

[John Strung]

Do you have WEP enabled on the ABS, but not on the client?

[cpac]

Originally posted by John Strung:
Do you have WEP enabled on the ABS, but not on the client?

Not sure how I would check that - but I am able to connect to the internet through the ABS *some* of the time, it's just that I get booted periodically.

Where would I check whether WEP is enabled on the client machine?

[cpac]

I found this which suggests downgrading the firmware of the ABS to 4.0.7 may fix the problem.

I've downgraded and I'll post my results.

http://discussions.info.apple.com/We...Op.0@.599d165d

[cpac]

[edit: nope - verdict is still out]